MEDUSA. I. J, 



leave the periphery of the stomach, 3-3-3-3, and 11 canals reach the circular vessel. One of the qua- 

 drants is stunted, pressed between the neighbours; in connection lierewith it must be remarked tiiat 

 the specimen is unusually highh- arched. The arrangement of the canals is as follows: 



Group I. 3 canals (marked i, 2, and 3 in the figure) leave the stomach and reach the circular 

 vessel (as to No. i, see below). 



Group II. 3 canals (4, 5, 6) leave tlie stomach and reach the circular vessel in normal wa>-. 



Group III. 3 canals (7, 8, 9) leave the stomach. No. 7 reaches the circular vessel normally; No. 8 

 divides into 8 a and 8 d, both of which reach the circular vessel. No. 9 runs to the margin and reaches 

 tlie circular vessel so near No. i, that tliere is onl\- room for 3 tentacles between the two canals. On 

 the way towards the margin No. 9 sends out a branch (x), which, crossing No. i, runs towards the 

 margin and reaches the circular vessel between No. i and 2, nearest to No. i. 



Group IV. 3 canals leave the stomach, all ver)- close together, and unite just outside the sto- 

 mach into one canal, which opens into the link canal x between 9 and i, nearest to No. 9. 



The arrangement of the gonads on the abnormal radial canals is sketched in the figure. 



Only in a few cases it has been possible to count the tentacles and marginal vesicles. 

 Loc. No. 3, specimen No. II (diam. 45 mm) has 442 tentacles, the distribution of which in rela- 

 tion to the 13 radial canals will be seen from tlie following scheme: 



Off the 13 radial canals 13 tentacles 



Group I 19 + 49 + 30 =98 — 



— II 25 + 34 + 27 =86 — 



— 11146 + 29 + 34 + 32 = 141 — 



— IV 29+37+38 = 104 - 



Total ... 442 — 



Thus the number of tentacles between two successive radial canals varies, in this specimen, from 19 to 49. 

 Loc. No. 9, specimen No. Ill (diam. 44 nun) has 16 radial canals (arrangement irregular), 428 

 tentacles, and 80 marginal vesicles, distributed between the radial canals in the following manner: 



Tentacles 10 29 28 1631 23 25 28 31 20 11 36 28 36 29 31 



Marginal vesicles i 762 5454 S3 369656 



Thus in the present case the number of tentacles between two successive radial canals varies from 

 10 to 36, the number of marginal vesicles from i to 9. The average number of marginal vesicles be- 

 tween two canals is 5.35, the average number of tentacles between two successive marginal vesicles is 

 5.70. The arrangement of the marginal vesicles is, however, fairl\- irregular, in so far as two vesicles 

 may be found immediately beside each other. 



Specimen No. IV from the same locality (diam. 56 mm) has 14 radial canals (3-3-4-4); the tent- 

 acles cannot be counted; there are 83 marginal vesicles, distributed between the radial canals in the 



following manner: 



4354785 ^0379 567 



The average number of marginal vesicles between two successive radial canals is 5.9, varying from 3 to 10. 



The Ingolf-Expedilion. V X. *^ 



